This jet quenching program faces two major challenges.
Firstly, jet evolution in heavy-ion collisions involves multiple stages of
physics that are not known from first principles, such as the initial state of the collision,
the hydrodynamic evolution of the medium, and the hadronization phase.
This can be addressed by global analyses that fit phenomenological models to a wide range
of experimental data, and has recently been solved to a
large extent.[1]}, [2]}, [3]}, [4]}, [5]}
A second challenge, however, is that jet evolution in the QGP,
even for a perfectly characterized medium, involves
numerous theoretical unknowns, from
the strength of coupling of the jet-medium interaction to the role of factorization breaking
and color coherence. No (known) golden observable exists to disentangle these open questions
about the jet-medium interaction.
This necessitates global analyses of multiple jet observables.
Such global analyses provide a viable path not only to
disentangle various theoretical approaches describing the jet-medium interaction
but also to precisely determine medium properties from experimental measurements –
the ultimate goal of studying the QGP.
